Apparatus for ramming flasks



Feb. 14, 1950 M. G. CLAY 2,497,585

APPARATUS FOR RAMMING FLASKS Filed June 7, 1945 4 Shets-Sheet 1 Feb. 14, 1950 i M. e. CLAY 2,497,585

APPARATUS FOR RAMMING FLASKS Filed June 7, 1945 4 Sheets-Sheet 2 Feb. 14, 1950 M. G. CLAY 2,497,585

APPARATUS FOR RAMMING FLASKS Filed June 7, 1945 4 Sheets-Sheet s l atenteci APPARATUS FOR RAMMING FLASKS Murray G. Clay, Chicago, IlL, assignor, by mesne assignments, to Pettibone Mulliken Corporation, a corporation of Delaware Application June '7, 1945, Serial No. 598,145

8 Claims.

The invention relates to filling flasks with sand for molds.

In ramming flasks with sand by means of sand projectors in foundry installations, it is sometimes advantageous, particularly where large volumes of sand are projected into the flasks, to provide stationary tanks for the backing and facing sand used, and to feed the sand to a power-driven projector which travels on a track on the foundry floor to successively ram rows of flasks, by a stationarily mounted conveyor extending along the track, the projector being adapted to travel along the conveyor to receive a constant supply of sand for delivery into the flasks. It is also advantageous to provide a seat or support for the operator which is movable with the projector, so the operator can observe the distribution of the sand in the flasks, and to control the operation of the sand-delivery mechanism and the projector by the operator. It is frequently necessary to use different kinds of sand, such as facing and backing sand and to stop the projector and sand delivery when the projector is moved from flask to flask or for other purposes. In these installations, it is also desirable to operate the projector at diiferent speeds for varying the density of the sand in the flask and, for this purpose, it is necessary to vary the volume of sand delivered to the projector by the sand-delivery system. A desideratum is to control the operation of the motors for driving the projector and for delivering sand from stationary tanks by mechanism within reach of the operator mounted on the projector.

One object of the invention is to provide a sand-delivery mechanism which is controlled by the operator on the portable sand projector so that he may conveniently control the operation of the projector, the sand-conveyor, and the feeding mechanism which delivers the sand from stationarily mounted tanks to the projector. When the sand-system is thus controlled, it is not necessary to have an additional or assistant operator for controlling the motors which operate the sand-delivery system and the operator for the projector has complete and quick control of the sand-feeding system, as well as the sand projector.

In these installations, it is necessary to use trolleys for supplying electric current to the electric motors on the projector and it is desirable, in the control of the sand-delivery mechanism by the operator on the projector, to use a minimum number of trolleys.

Another object of the invention is to provide control mechanism on the projector for the motors of the sand-delivery system through a single additional trolley and which controls the starting of the motors for feeding different kinds of sand and different volumes of the sand to the projector.

Another object of the invention is to provide simple and eflicient switching mechanism for controlling the operation of the motors for driving the sand projector, the sand feeding mechanisms, and the sand-conveyors.

Other objects of the invention will appear from the detailed description.

The invention consists in the several novel features which are hereinafter set forth and are more particularly defined by claims at the conclusion hereof.

In the drawings: Fig. 1 is a plan of an installation comprising an overhead stationarily mounted sand-delivery system and a sand projector mounted to travel over the foundry floor and to be supplied with sand from said system. Fig. 2 is a side elevation of the projector and sand-delivery system. Fig. 3 is a section of one of the tanks from which sand is discharged to the sand-conveying mechanism. Fig. 4 is a diagram of the switch mechanisms and electrical connections for controlling the sand-delivery system and the projector. Fig. 5 is an end elevation of the projector and the switch mechanism mounted thereon. Fig. 6 is a section showing the wheeled supporting frame for supporting the projector mechanism. Fig. 7 is a section taken on line 1-1 of Fig. 6.

The invention is exemplified in an installation which comprises a portable frame or carriage 0' which is supported on flanged wheels 0 Wheels 0 are adapted to travel on a rail 0 The upper end of carriage 0 is provided with wheels 0 which are adapted to travel in the channel of a rail 0 Rails 0 and 0 form a track which extends longitudinally of the bay of the foundry in which the flasks are to be rammed. The carriage constitutes a portable support for the projector mechanism. The carriage is usually equipped with an electric motor s and a belt drive s for driving one of the wheels 0 to propel the carriage and projecting mechanism carried thereby over the foundry floor.

A rotary sand projector o is mounted to travel with the carriage so that it can be moved for ramming flasks distributed over the floor of the foundry. The casing of the sand projector o is fixedly supported by a jib [2 which is pivotally supported at the outer end of an arm l3 which is pivoted to swing horizontally in a housing I4 so that the projector, by the compound or independent swinging of said jib and arm, may be moved over flasks on the floor of the foundry to distribute the sand throughout all portions of the flask. Housing M is supported by parallel arms l5 and I6 which are pivoted to housing It and the supporting frame for vertical adjustment of said housing and the projector. A seat 24 for the operator is mounted adjacent the end of the casing or projector 0 so the operator can observe the distribution of sand in the flasks. The swinging movements of jib l2 and arm !3 may be controlled by a hand lever 21 and hydraulic mechanism (not shown) of the type exemplified in Patent No. 2,339,001. An endless driven conveyor I! which is mounted to swing with jib. i2, is adapted to feed sand through an opening in the inner side of the housing of projector a into the path of a rotary blade, as is well understood in the art. for projection into the flasks. An endless driven conveyor is mounted to swing with arm i3 is adapted to convey sand onto the belt H. An endless driven conveyor I9 is adapted to receive sand from a conveyor extending. over the track 0 and deliver it onto the conveyor I8, Conveyors I9, [8 and H are adapted v to continuously deliver sand to the projector for motor g. When a hydraulic, system is used for shifting the jib l2 and arm 63 for moving the projector over the flask, a motor h (Fig. 4) is provided for forcing oil. under pressure to the control mechanism, as exemplified in the aforesaid, Patent No. 2,339,001. A starting relay come prising a magnet it. controls the operation of the motor h.

The overhead sand-delivery system for supplying sand to the. projector comprises a tank [0 for holding a supply of facing sand; a pair of tanks i! and II eachfor holding a supply of backing sand; an endless conveyor 9 adapted to receive sandfrom any of the tanks til, it and i2; and an endless conveyor 9 which receives sand from conveyor 9 and parallels the path of travel of the carriage o for the projector. A strike 8 is mounted to travel with the frame 0* and to engage the sand on the conveyor 9 and deflect it onto the end of the conveyor i9 below said conveyor. Tanks It, H and li' and conveyors Q and 5 are supported by a suitable framework 1 at a higher level than frame 0' so that sand will be delivered by gravity onto the conveyor it.

Each of the tanks Ill, II and N is provided with a rotatable bottom or disk r and a discharge chute r through which the rotatable bottom feeds the sand in regulated quantity into a hopper T which deposits. the. sand onto the conveyor 9. Each bottom r is driven by an electric motor through reducing gearing r 2. bevel pinion r and a bevel gear 1 fixed to. the, bottom. A two-speed electric motor a is provided for driving the gearing which drives the disk 1" under tank ll! for feeding facing sand from said tank onto the conveyor 9. A starting relay comprising magnets a, a (Fig. 4) is adapted to shift two three-switch sets to control the operation of motor a at two predetermined speeds to vary the rate of discharge of the sand from said tank according to the speed of operation of the projector. A smiliar two-speed electric motor b is adapted to drive the bottom 1" under tank H for feeding sand. from said tank onto the conveyor 9. A starting relay comprising magnets b, b (Fig. 4) and two three-switch sets, is provided for controlling the operation or" motor b at two predetermined speeds to vary the rateof discharge of sand from tank H to conveyor 8. A two-speed electric motor c is provided for driving the bottom 1' of tank H to feed sand from said tank onto conveyor 9. A starting relay comprising magnets c, c is provided for controlling the operation of motor 0 at two predetermined speeds to vary the volume of sand fed from said tank onto conveyor 9. A two-speed electric motor (1 is provided for conj'ointly driving conveyor belts 9 and 9 through gearing, and to drive them at the same surface speed. A starting relay comprises magnets d, d and two three-switch sets for controlling the operation of motor d and its speed to drive belts 9 and 9* at the two different speeds for delivering sand to the projector at the rate at which it is fed from the supply tanks.

Each ofthe motors a, b, c and d is of the threephase two-speed type for the operation of the motors at two predetermined speeds, for example, 1200 and 1800 R. P. M., and these motors are automatically controlled so that when the projector motor gr, is operated at high speed the motors a, b, c and 01 will be operated at a correspondingly high speed for the delivery of a sufficient volume of sand to. keep the projector supplied while itis operating at high speed and so that when the projector is, operatedat its low speed the motors a, b, c. and (1 will be operated at a correspondingly. lower speed to properly vary the volume. of sand delivered to. the projector.

Current is supplied byline-conductors e, e and e which are: connected respectively to stationary trolley rails ,f, f Trolley wheel f i f are mounted on carriage 0' so as; to travel with the projector and engage said rails to supply current to the motor g on the. projector and other motors which are adapted to travel with carriage o. A fourth trolley rail f is provided and engaged by a trolley wheel i also carried by carriage o for supplying current to circuits for controlling the motors of the sand-delivery system. The motors a; b, c and (1 receive current from the line conductors e, e and e through their starting relays.

A switch mechanism m is mounted on the projector-casing adjacent the operators seat 2-4 for controlling the operation of the stationarily mounted motors. a, b, c and d of the sand-delivery system. This mechanism m also controls the motor g for driving the projector and the pump motor h which are mounted to travel with carriage 0' which travels relatively to the sanddelivery system. This switch mechanism is connected to the trolley-wheels f f 1' and i as illustrated in Fig. 4', and comprises a manually shiftable lever m. movable between a series of eight stations; a segmental contact 35 engageable by a contact 33 on lever m for controlling the operation of magnet 71. which controls the pump motor 71; a segment. 3? engageable by a contact 3 on lever m for controlling magnet g which controls the operation of' the projector motor 9 at low speed; a segmental contact 38 engageable by feeding facing sand to conveyors 9, 9

a contact 34 on lever m for controlling the magnet g which controls the high-speed operation of the projector motor 9; and a series of six contacts 63 engageable respectively by a contact 32 on lever m for transmitting impulses for operating an auto transformer or relay n for shifting switch mechanism 2 which is stationarily mount- .ed and is adapted to selectively control the relays Contact 45 is rotatable between seven stations and at station 3 engages one of the contacts 62 for energizing magnet a for starting and controlling the low speed operation of the motor a for feeding facing sand to the conveyor 9. At station contact 45 engages another contact 62 for energizing magnets b or c for starting and controlling the low speed operation of motors b and 0, respectively, for feeding facing sand to conveyor 9. At station 6, contact 45 engages another of the contacts 62 for energizing magnet a for controlling the high-speed operation of motor a for At station I, contact 45 engages another of the contacts 62 for energizing magnets b or for controlling the high-speed operation of motors b or 0. Contact 44 is engageable with segments 49 and 5D for circuits through magnets d, d respectively, for controlling the low and high-speed operation of the motor (1 which drives the conveyors 9, 9 of the sand delivery mechanism.

An autotransformer or relay n is provided for rotating the contacts 44 and 45 of switch mechanism l by electrical impulses responsive to the movements of the lever m of the switch mechanism m. This relay 11 comprises a pair of magnets 53, 54; an armature-lever 5B, the ends of which are shiftable by said magnets, respectively; pawls 5'! and 58 connected to the ends of lever 56; and a toothed wheel 11' adapted to be advanced step-by-step in clockwise direction by the pawl 57 and in counterclockwise direction by the pawl 58 responsive to impulses through the magnets 54, 53, respectively. The relay 1:. also comprises a coil 11 the ends of which are connected by conductors 59 and 60 to the trolley-rails f respectively. A conductor 6| connects the trolleyrail f to the helices of magnets 53, 54. The other ends of said helices are connected to the coil n between its ends, as illustrated in Fig. 4, so that when current of 220 volts is used, current of 165 volts will pass through the helix of magnet 54 when the current flows to the coil from con ductor 5| to conductor 60 and the current through the helix of magnet 53 will be reduced to 55 volts.

. The higher voltage through magnet 54 will cause it to operate lever 56 and pawl 58 to shift wheel n one step in counterclockwise direction. When current flows to coil 11 from conductor 59, the helix of magnet 53 will receive 165 volts while magnet 54 will receive only 55 volts, which will cause lever 56 to operate pawl 51, so as to advance wheel 11' one step in clockwise direction. Toothed wheel n is fixed to the rotatable segments 42, 43 and contacts 44, 45 of switch mechanism 1 so that they will be rotated step-by-step in either direction by the relay n to selectively control the 6 operations of motors a, b, c and d from the lever m of the switch mechanism m which travels with the projector.

Contacts 30, 3| of switch mechanism m are provided to swing on the pivot of and relatively to lever m and their outer ends are normally pressed by springs m into a centralized position and out of engagement with said lever. When the handle of lever m is shifted in counterclockwise direction, it will compress the lower spring m and engage contact 3| and, when shifted in the opposite direction, it will compress the upper spring m and engage contact 30.

Contacts 63 of switch mechanism m are disposed to be engaged by contact 32 on lever 11: between the indexed stations at which the lever is stopped. As a result, when the handle of lever m is shifted in counterclockwise direction between stations 2 and 8 of said lever, contact 3| will be engaged by lever m and between each of said stations, contact 32 will make momentary contacts with the contacts 63 and at each contact 33 will establish a circuit for energizing magnet 54 to operate contacts 44, 45 and segments 42 and 43 one step in counterclockwise direction. During shift of the handle of lever m in clockwise direction from stations 8 to 2, lever m between each two stations will engage contact and momentarily establish a circuit through one of the contacts 63 for energizing magnet 53 for operating contacts 44, and segments 42 and 43 step-by-step in clockwise direction. The circuit for impulses to magnet 54 for imparting operative strokes to pawl 58 to rotate wheel 11' in counter-clockwise direction will be as follows: trolley-wheel f conductor 66, contact 3|, lever m, contact 32, one of the contacts 63, conductor 68, trolley-wheel f trolley rail f conductor 6|, magnet 54, coil n conductor 59, and trolleyrail ,f. The circuit for impulses through magnet 53 for operating the toothed wheel 11. and contacts 44 and 45 of mechanism Z in clockwise direction will be as follows: trolley-wheel f conductor 64, contact 33, lever m, contact 32, one of the contacts B3, conductor 58, trolley-wheel f trolleyrail 1 conductor 6|, the helix of magnet 53, coil n conductor 60, and trolley-rail F.

The switch mechanism m, which is mounted to travel with the projector, controls the motor g for operating the projector at predetermined high and low speeds and the motor h for driving the pump motor, and is adapted, by the selective movements of lever m, through the switch mechanism Z and relay n, to control the operation of the motor d for driving the sand-conveyors 9, 9,

the motor a for feeding facing sand, and the motors b and .c for feeding backing sand onto the conveyors at predetermined high and low speeds.

When lever m is at station I, as shown in Fig. 4, all of the motors will be idle; at station 2, pump-motor it will be started and operated at low speed; at station 3, motor 9" for driving the projector and motor d for driving the sand-conveyors 9, 9 will be operated at the low predetermined speed; at station 4, the projector motor g, the motor d for driving the conveyors 9, 9 and the motor a for feeding facing sand to said conveyors will be operated at low speed; at station 5, the projector motor 9, the motor d for driving the sand conveyors 9, 9 and the motor b or c for feeding backing sand onto the conveyors will be driven at low speed; at station 5, projector motor 9 and the motor d for the endless conveyors 9, 9 will be operated at high speed and the motors it, b and will be idle; at station 1, the projector motor 9', the motor at for driving the sand 'conveyors and the motor a for feeding facing sand to said conveyors will be driven at high speed; and at station 8, the projector motor 9, the motor at for driving the sand convey'ors 9'; 9 and either one of the motors b or c for feeding bacliing sand onto the conveyors, will be driven at high speed.

The operation will be as foilows: when lever m" of switch mechanism which is movable with and by the operator seated attire projector, is in its normal position, as illustrated in Fig. 4, all of the circuits for the operation of the motors for driving the sand delivery apparatus and the motors on the projector will be open and all of said motors will be idle.- Whenthe operator shifts lever m to station 2', the motors in for driving the pump for supplying oil under pressure to the hydraulic mechanism (not shown) for shifting the projector arm is and jib l2 will be started while the motor g for operating the projector is idle. At station 2', the following circuit will be established for energizing magnet h to close the switches for the operation of motor it, viz: trolle'y-wheel f conductor 54, contact 33 on lever m, segment 35, conductor 36, the helix of magnet h, conductor 65, and trolley-wheel f Motor it will then start and remain in operation until lever m is again restored to itsnormal position at station I. When lever m is atv station 2, all motors except motor h will remain idle;

When the operator shifts lever m to station 3, the following circuit will be established to start the" motor 9 for driving the projector, viz: trolleywheel I", conductor 64, contact 34-, segment 3!, conductor 38', the helix of magnet g, conductor 56 and trolley-wheel f Magnet y will then close the contacts for the operation of motor g coiitact 3|, lever m, contact 32,- Contact 83, condiictor 68, trolley-rail f conductor iii; the helix of magnet 54, a portion of coil n conductor 60 and tr'olley rail f Magnet 54 will imparta stroke to lever 56 and shift pawl 58 to rotate wheel 1i arid contacts 45 and 85 one step in counterclockwise direction. Contact 44 will then engage segment 39 and close the following circuit for starting the motor at to drive the conveyors 9 and 5 at low speed, viz: line conductor e, trolleyrail 1, conductor 59', contact 6, segment 42; contact 44, segment l9, conductor Iii; the helix of magnet d and conductor e Magnet d holds the switches for the operation of the motor (1 at low speed closed while contact 45 is at stations 2, 3 and 4 to deliver sand to the projector at the desired rate for the operation of the projector at low speed, for example 1200 R. P. M.

When the operator shifts lever m from station 3 to station 4, the circuit through magnet 55 will again be momentarily closed at contact 31 to again rotate wheel a and contacts 45, 45 of switch mechanism Z one step in counterclockwise direction. The following circuit will then be establis'hed for starting the motor a for the delivery or facing sand from tank It to conveyors 9, 9

at the desired rate for the low speed operation or the projector, viz: line conductor e conductor 18, contact 4?, segment 43, contact 45, contact 62 at station 3 of switch mechanism Z, conductor M, the helix of magnet a, conductor [5, segment 49; contact 44, segment 42, contact 36; conductor 59, trolley-rail f, and line conductor e; Magnet a will then close the switches for the operation of motor a at the predetermined low speed for delivering facing sand from tank it onto the conveyors 9 and 9 for delivery to the projetoi.

When it is desired to supply backing, in lieu of facing, sand to the projector for delivery into the flasks at low speed, the operator will shift lever m. to station 5 of the switch mechanism in which will again close the circuit for again operating the magnet 54 to advance wheel n another step in counterclockwise direction, and shift coritact into engagement with the contact 62 at station 4 of the switch mechanism Z. This will interrupt the circuit for magnet a at contact 45 to stop motor a and'close the following circuit for starting and operating motor b at low speed, viz: conductors e F8, contact c1, segment '43, contact 62 at station 4 of switch mechanism 2, conductor 15 in which one of the members of switch It is included, the helix of magnet 2), conductor Hi, segment E9, contact 44, segment 42, contact 46, conductor 59, trolley-rail f, and conductor e. Magnet b will then close the switches for the operation of motor I) for the delivery of backing sand to the conveyors 9, 9 at the desired rate for the low-speed operation of the projector.

when the sup y of backing sand from tank u is exhausted and it is desired to supply sand from tank H switch is will be reversed and the magnet 0 will he energized to close the circuits for the operation of motor c at low speed. The oilsun: will then be conductor it through the upper member of switch It, conductor I? and magnet e in lieu or magnet 17.

When it is desired to operate the projector at high speed, for example, 1-800 R. P. the opcrater will shift lever iii to station 6 of switch mechai'lism This will interrupt the circuit for magnet g at contact 34 and segine'nt 31 and close a circuit through m'a'gnet p for closing the switches for establishing circuits for operating the motor g at high speed. when lever m is shifted to station 6, the following Circuit Will be established for energizing magnet g viz: trolley-wheel 1' conductor 64, Contact 34, segment 38, conductor it, heliii of magnet 9 conductor $6 and trolley-wheel f so that magnet 51 willclose the switches for starting and operating the motor g at high speed.

The circuits for the operation of the projector motor g at high speed will remain closed while lever m is at or between stations 6, i and 8 of switch mechanism m, so that the projector motor will remain running. lever m" is shifted from station 5 to station 6, the circuit through lever m and contact 3! will again be closed to operate magnet ti for the rotation of wheel and contacts '44 and 45 in counterclockwise direction to station 5 of mechanism 1. At said station or mechanism 1, contact -45 will be 'disconnected from the circuits for magnets a and b andrc, so that the motors for feeding sand to the conveyors 9, ii will be idle. When contact 34 leaves segment 4s between stations A and 5, it will interrupt the circuit through magnet d to open the switches for the low-speed operation of motor d. When contact 44 is at station 5 of mechanism 1, it will engage segment 50 and establish the following circuit for starting motor 11 at high speed, viz; conductor 59, contact 46, segment 42, contact 44, segment 50, conductor 19, the helix of magnet d conductor 18 and conductor e Magnet (1 will then close the switches for the operation of motor d at high speed.

When lever m is shifted to station I, the circuit through contact 3| and lever m will again be closed. Magnet 54 will again be operated to rotate contacts 44, 45 of mechanism Z one step in counterclockwise direction and bring said contacts to station 6 of mechanism Z. The following circuit will then be established for closing the switches for the high-speed operation of the motor a, viz: conductor 18, contact 4'1, segment 43, contact 45, contact 62 at station E, conductor 8|, helix of magnet a conductor 19, segment 50, contact 44, segment 42, contact 46, and conductor 59. Magnet a will then close the switches for the high-speed operation of the motor a for delivering facing sand to the corn veyors 9 and 9.

When it is desired to deliver backing sand at the high rate to the projector, the operator will shift lever m to station 8 of switch mechanism m, which will again close the circuit for the operation of magnet 54 to rotate wheel n one step in counterclockwise direction and shift contacts 44, 45 to station 7 of mechanism Z. The following circuit will then be established for the high-speed operation of motor I) for delivering backing sand onto the conveyor, viz: conductors e 78, contact 41, segment 43, contact 45, contact 52 at station 1, conductor 82 in which one member of switch k is included, the helix of magnet b conductor (9, segment 50, contact 44, segment 42, contact 46, conductor 59, trolley-rail j, and conductor e. Magnet 22 will then close the switches for operating one motor b at high speed. If the switch k: is reversed, the magnet will be energized to close the switches for motor 0, in lieu of those for motor I).

When the handle of lever m is shifted in clockwise direction between stations 8 and 2, said lever will engage contact and successively establish circuits for impulses through magnet 53 for shifting wheel n and contacts 44, stepby-step in clockwise direction. This circuit for each impulse will be as follows: trolley-wheel f conductor 64, contact 30, lever m, contacts 32, 63, conductor 68, trolley-wheel f conductor El, the helix of magnet 53, a portion of coil n conductor 59, trolley-rail f, and conductor 6. Each operation of magnet 53 will rock lever 58 to cause pawl 51 to rotate wheel 11 one step in clockwise direction and correspondingly rotate contacts 44 and 45 of mechanism I so that, during the return of lever m to its normal position, the circuits previously described for the operation of all of the motors at the intermediate stations, will be established in reverse order. Fixed stops 5! are provided to limit the movement of contact 44 and fixed stops 52 are provided to limit the move" ment of contact 45.

The invention is not to be understood as restricted to the details set forth, since these may be modified within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire to secure by Letters Patent is:

1. Control mechanism for apparatus including a rotary sand projector mounted on a structure adapted to travel over a floor, stationarlly mounted apparatus for delivering sand from a source of supply to the projector when it is moved to different positions over the floor, a stationarily mounted plural-speed electric motor for driving the sand delivery apparatus and an electric plural-speed motor for driving the projector, mounted to travel with the structure, said control mechanism comprising a manually and selectively operable control device mounted to travel with the projector, and means operable by said device for conjointly controlling the operation and speed of the motor for driving the delivery apparatus at different speeds and operation of the motor for driving the projector at different speeds.

2. Control mechanism for apparatus including a rotary sand projector mounted on a structure adapted to travel over a floor, stationarily mounted apparatus for delivering sand from a source of supply to the projector when it is moved to different positions over the floor, a stationarily mounted electric motor for driving the sand delivery apparatus and an electric motor for driving the projector, mounted on and to travel with the structure, said control mechanism comprising a man ually and selectively operable switch device mounted to travel with the projector, means controlled by said device for controlling the operation of the motor for driving the projector, stationarily mounted switch mechanism for conjointly controlling the operation of the motor for driving the sand delivery apparatus at different speeds, and means, responsive to impulses controlled by said device, for shifting said switch mechanism.

3. Control mechanism for apparatus including a rotary sand projector mounted on a structure adapted to travel over a floor, stationarily mounted apparatus for delivering sand from a source of supply to the projector when it is moved to different positions over the floor, a stationarily mounted plural-speed electric motor for driving the sand-delivery apparatus and an electric plural-speed motor for driving the projector, mounted to travel with the structure, said control mechanism comprising a manually and selectively operable switch device mounted to travel with the projector, for controlling the operation of the motor for driving the projector at different speeds, a stationarily mounted switch mechanism for conjointly controlling the operation of the motor for driving the sand-delivery apparatus at different speeds, and means controlled by said device, for shifting the switch mechanism to control the operation and speed of the motor for driving the sand-delivery apparatus.

4. Control mechanism for apparatus including a rotary projector mounted on a structure adapted to travel over a floor, stationarily mounted conveying-means for delivering sand to the projector when it is moved to different positions over the floor, a stationarily mounted plural-speed electric motor for driving the sand-conveying means, means for feeding sand from a source of supply onto the conveying-means, an electric pluralspeed motor for driving said sand-feeding means, and an electric plural-speed motor for driving the projector, mounted on and to travel with the structure, said control mechanism comprising a manually and selectively operable control device mounted to travel with the projector, and means controlled by said device for conjointly controlling the operation of the motor for driving at different speeds the conveying-means, the operation of the motor at different speeds for driving aeezcee the sand-feed means, and the operation and speed of the motor for driving the projector.

5. Control mechanism for apparatus including a rotary projector mountedon a structure adapted to travel over a door, stationarily mounted conveying-means for delivering sand to the projec'tor when it is moved to difierent positions over the floor, a stationarily mounted plural-speed electric motor for driving the sand-co veying means, means for feeding sand from a source of supply onto the conveying-means, an electric plural-speed motor for driving the sand-feeding means, and an electric plural-speed motor for driving the projector, mounted on and to travel with the structure, said control mechanism comprising a manually and selectively operable control-switch device mounted to travel with the project-or, means controlled by said device for conjointly controlling the operation and speed of the motor for mounted switch mechanism for controlling the operation and speed of the motors for driving the conveying-means and the sand-feed means, and means responsive to impulses controlled by said device for shifting said switch mechanism.

6. Control mechanism for apparatus including a rotary prjector mounted on a structure adapted to travel over a floor, stationarily mounted conveying means for delivering sand to projector when it is moved to different positions over the floor, a stationarily mounted plural-speed electric motor for driving the sand-conveying means, means for feeding sand from a source of supply to the conveyingmeans, an electric plural-speed motor for driving said sand-feeding means, and

an electric plural-speed motor for driving the projector, mounted on and to travel with the structure, said control mechanism comp-rising a manually and selectively operable control switch device mounted to travel. with the projector, means controlled by said device for conjointly controlling the operation and speed of the motor for driving the projector, stationarily mounted switch mechanism for controlling the operation and speed of all of the stationarily mounted motors, and means operable by electric impulses controlled by said device, for selectively shifting the switch mechanism to control the operation and speed of the stationarily mounted motors.

7. Control mechanism for apparatus including a rotary projector mounted on a structure adapted to travel over a floor, stationarily mounted conveying-means for delivering sand to the projector when it is moved to different positions over the door, a station-aril mounted plural-speed electric motor for driving the sandconveying means, mechanisms for feeding sand from a plurality of sources of supply to the conveyingmeans, plural-speed electric motors for riving the projector, stationarily driving said sand ieeding mechanisms, respectively, and an electric plural-speed motor for driving the projector, mounted on and to travel with the structure, said control mechanism com prising a manually and selectively operableswitch device mounted to travel with the projector, means controlled by said device for conjointly controlling the operation and speed of the motor for driving the projector, stationarily mounted switch mechanism for controlling the operation and speed of all of the stationarily mounted motors, and means operable by electric impulses controlled by said device, for selectively shifting the switch mechanism to control the operation and speed of the stationarily mounted motors.

8. Control mechanism for apparatus including a rotary sand projector movably mounted on a structure adapted to travel over a floor, stationarily mounted conveying-means for delivering sand to the projector when it is moved to dire ferent positions over the floor, a stationarily mounted plural-speed electric motor for driving the sand-conveying means, mechanism for feeding sand from a source of supply to the conveying-means, an electric plural-speed motor for driving the sand-feeding mechanism, an electric plural-speed motor for driving the projector, mounted to move with the projector and to travel with the structure, said control mechanism comprising a manually and selectively operable control device mounted to move with the projector, means controlled by said device for conjointly controlling the operation and speed or the motor for driving the projector, stationarily mounted switch mechanism comprising a rotatable member for controlling the operation and speed of all of the stationarily mounted motors, and a stationary relay comprising a toothed wheel connected to rotate member and magnets for shifting the Wheel step-by-step in opposite directions to shift the rotatable member, said control device comprising switch contacts for controlling the movement of the wheel in opposite directions.

MURRAY G. CLAY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,335,6 ll Beardsley et a1. Mar. 30, 1920 1,395,089 Burhans Got. 25, 1921 1,439,871 Coulter Dec. 26, 1922 1,816,612 Piper July 28, 1931 2,054,338 Piper Sept. 15, 1936 2,212,510 fjlay Aug. 27, 1940 2,339,001 Clay et al. Jan. 11, 1944 OTHER REFERENCES Unusual applications of motor control, published in Iron and Steel Engineer (Pittsburgh, Pa.) June 1945, pages 50'53. 

